In general, persons wishing to contact a particular party initiate a call to a telephone specifically known to be associated with that party, such as the party's office or wireless telephone. A disadvantage of this method of communication is that parties are not always in close proximity to such associated telephones, or for that matter, in close proximity to any telephone. This presents a problem to persons who need to immediately contact a mobile party, regardless of that party's location.
Several technologies have developed in an effort to solve the problem of establishing communication with a mobile party. These include call forwarding, paging, and cellular systems. However, each of these technologies has drawbacks which prevent seamless and ubiquitous communication.
The inventions disclosed in the Ser. No. 08/379,425 and Ser. No. 08/379,430 applications (the '425 and '430 inventions, respectively), cited hereinabove, address many of the problems associated with prior systems used to communicate with mobile individuals. Both of those inventions describe a call routing scheme in which each subscriber is assigned a Personal Telephone Number (PTN) and uses a two-way pager to route calls placed to that number. In the '430 invention, when a call is placed to the subscriber's PTN, a network database query is generated and information about how to handle the call is retrieved (referred to as "registration" type routing). In the '425 invention, when a call is placed to the subscriber's PTN, the subscriber's pager number is retrieved from the database and an alerting page is sent to the subscriber. The subscriber may then use the two-way pager to transmit a terminating number back to the network in response to the alerting page (referred to as "call-by-call" type routing).